Hah, I didnt think about stopovers. Well since my vacation is flexible I think I'm going to go with a few days in Paris.
Instead of going with AF (convenience), I'm going to use BA with the 10% chase to get $1100 LAX-JNB; JNB-CDG; CDG-LAX (all through LHR).
It would have been nice to use the $900 AF ticket but the discount fare doesn't allow for the stopover.
Back to the original post: $1800 just seems like way too much for WTP and the chances at upgrading each leg. And I called BA and it appears I can't just pick and choose a few legs to upgrade
Thanks again for the advice! Love this forum!